Various header compression mechanisms to reduce header overhead of packets transmitted over a network (e.g., Internet) have been introduced in recent years. For example, header compressions under compressed transfer control protocol (CTCP), compressed real time transport protocol (CRTP) and robust header compression (ROHC) have been widely used, especially, in voice over internet protocol (VoIP) applications. However, those header compression mechanisms are designed for specific networks or traditional usage models, regardless of changeable network environment, different types of the packets, user's preference for header compression and the like. Same situations exist in header decompression for the packets received through the network.